From 77b12f809bd576e008a0bf931dd09f9e10593228 Mon Sep 17 00:00:00 2001 From: Ramiro Polla Date: Sun, 26 Apr 2009 20:37:40 +0000 Subject: mlpdec: Simplify filtering code by using only one counter variable. Originally committed as revision 18695 to svn://svn.ffmpeg.org/ffmpeg/trunk --- libavcodec/mlpdec.c | 25 ++++++++++++------------- 1 file changed, 12 insertions(+), 13 deletions(-) (limited to 'libavcodec/mlpdec.c') diff --git a/libavcodec/mlpdec.c b/libavcodec/mlpdec.c index 8f87cce351..cb1e279700 100644 --- a/libavcodec/mlpdec.c +++ b/libavcodec/mlpdec.c @@ -700,17 +700,18 @@ static void filter_channel(MLPDecodeContext *m, unsigned int substr, unsigned int channel) { SubStream *s = &m->substream[substr]; - int32_t firbuf[MAX_BLOCKSIZE + MAX_FIR_ORDER]; - int32_t iirbuf[MAX_BLOCKSIZE + MAX_IIR_ORDER]; + int32_t fir_state_buffer[MAX_BLOCKSIZE + MAX_FIR_ORDER]; + int32_t iir_state_buffer[MAX_BLOCKSIZE + MAX_IIR_ORDER]; + int32_t *firbuf = fir_state_buffer + MAX_BLOCKSIZE; + int32_t *iirbuf = iir_state_buffer + MAX_BLOCKSIZE; FilterParams *fir = &m->channel_params[channel].filter_params[FIR]; FilterParams *iir = &m->channel_params[channel].filter_params[IIR]; unsigned int filter_shift = fir->shift; int32_t mask = MSB_MASK(s->quant_step_size[channel]); - int index = MAX_BLOCKSIZE; int i; - memcpy(&firbuf[index], fir->state, MAX_FIR_ORDER * sizeof(int32_t)); - memcpy(&iirbuf[index], iir->state, MAX_IIR_ORDER * sizeof(int32_t)); + memcpy(firbuf, fir->state, MAX_FIR_ORDER * sizeof(int32_t)); + memcpy(iirbuf, iir->state, MAX_IIR_ORDER * sizeof(int32_t)); for (i = 0; i < s->blocksize; i++) { int32_t residual = m->sample_buffer[i + s->blockpos][channel]; @@ -721,23 +722,21 @@ static void filter_channel(MLPDecodeContext *m, unsigned int substr, /* TODO: Move this code to DSPContext? */ for (order = 0; order < fir->order; order++) - accum += (int64_t) firbuf[index + order] * fir->coeff[order]; + accum += (int64_t) firbuf[order] * fir->coeff[order]; for (order = 0; order < iir->order; order++) - accum += (int64_t) iirbuf[index + order] * iir->coeff[order]; + accum += (int64_t) iirbuf[order] * iir->coeff[order]; accum = accum >> filter_shift; result = (accum + residual) & mask; - --index; - - firbuf[index] = result; - iirbuf[index] = result - accum; + *--firbuf = result; + *--iirbuf = result - accum; m->sample_buffer[i + s->blockpos][channel] = result; } - memcpy(fir->state, &firbuf[index], MAX_FIR_ORDER * sizeof(int32_t)); - memcpy(iir->state, &iirbuf[index], MAX_IIR_ORDER * sizeof(int32_t)); + memcpy(fir->state, firbuf, MAX_FIR_ORDER * sizeof(int32_t)); + memcpy(iir->state, iirbuf, MAX_IIR_ORDER * sizeof(int32_t)); } /** Read a block of PCM residual data (or actual if no filtering active). */ -- cgit v1.2.3